LS3 Vacuum lines

[130fe]

Scott is correct on both counts. I used the one in the back for my vacuum brake booster. I think it is a 1/2" fitting. I used a 1/2" TO 3/8" brass adapter fitting to convert the manifold fitting to my brake booster.

The steam line can go to either the radiator or plumb it into your water pump or heater hose lines. Will work either way.

[Timberline]

Thanks Che70velle and 130fe, that clears me up yes the one with the red cap is on the intake.
I am an old school Small Block/Big Block guy still figuring out the LS thanks for your help !